Abstract: In order to evaluate the toxicity reduction efficiency of the biological permeation reaction wall with microorganisms as the catalytic core, and explore the microbial carbon metabolism fingerprint and comprehensive metabolic activity characteristics in the process, a multi-level biological permeation reaction wall model was constructed and used for the treatment of actual landfill leachate. This study measured the dynamic removal rate of COD and microbial growth of the reaction wall during the treatment process, as well as the determination of functional microbial diversity and metabolic activity based on the Biolog method. The experimental results showed that the average daily COD removal rate for 7 days of operation was above 92%. The inhibition rate of luminescent bacteria is reduced by more than 60% compared with the original solution. The anti-oxidation activity of microorganisms in the reaction wall gradually increased with the treatment cycle, and the biological toxicity of effluent was significantly reduced. The functional microorganisms in the reaction wall maintained high biomass and metabolic activity, but the metabolic activity of microorganisms decreased with the increase of running time. After 72 hours of operation, the AWCD value of the back end was reduced by 23.6% compared with the front end, and the microbial evenness based on the metabolic diversity decreased by 25.2%. The research showed that the bio-permeable reaction wall contributed to COD removal and toxicity reduction of high-salt and high-concentration landfill leachates, and it has application value for the treatment of tannery wastewater with similar water quality to landfill leachate.